Electron spin orientation under in-plane optical excitation in GaAs quantum wells

Abstract

We study the optical orientation of electron spins in GaAs/AlGaAs quantum wells for excitation in the growth direction and for in-plane excitation. Time-and polarization-resolved photoluminescence excitation measurements show, for resonant excitation of the heavy-hole conduction band transition, a negligible degree of electron spin polarization for in-plane excitation and nearly 100% for excitation in the growth direction. For resonant excitation of the light-hole conduction band transition, the excited electron spin polarization has the same (opposite) direction for in-plane excitation (in the growth direction) as for excitation into the continuum. The experimental results are well explained by an accurate multiband theory of excitonic absorption taking fully into account electron-hole Coulomb correlations and heavy-hole light-hole coupling.

Temperature changes in the exciton absorption band observed in flat double nanoheterostructures GaAs/AlxGa1-xAs

“…However, despite the fact that up to date their optical properties have been studied rather well (see, for instance, [12]), including also the structure of excitonic spectra in these systems [13,14], respective investigations last till now [15][16][17][18][19][20][21][22]. In particular, using the quantitative analysis of experimental data, it was shown in [19] that the shape of spectral bands within the range of excitonic reflection inherent to heterostructures with GaAs single quantum wells (QWs) can be described in the first approximation via Lorentz oscillators.…”